Siemens Synco 700 Basic Documentation page 83

Control of the bypass
pump parallel to burner
operation
Maintained boiler return
temperature controlled
by mixing valve
Building Technologies
HVAC Products
TBo
ByPu
TRtBo
The bypass pump can be controlled either according to the acquired return temperature
or, when there is no sensor, parallel to burner operation.
Normally, the return temperature sensor is installed upstream of the bypass pump (on
the consumer side) to avoid too frequent switching of the bypass pump.
Main menu > Commissioning > Settings > ... or
Main menu > Settings > Boiler > Limitations
Operating line
Bypass pump switching diff
The return temperature is controlled with the bypass pump in 2-position mode within
the adjustable switching differential.
The pump will be activated when there is demand for heat and when the return tem-
perature drops below its minimum limit value.
The pump will be deactivated when the return temperature exceeds its minimum limit
value by the switching differential, or when there is no demand for heat.
TBo
60
50
40
30
10
Br
1
0
ByP
1
0
Br Burner
ByP Bypass pump
SDByP
Switching differential of bypass pump
t
Time
TBo Boiler temperature
TBoR Boiler return temperature
TBoRmin Minimum limit value of the boiler return temperature
TiOverrunCnsm Consumer overrun time
After the burner has been shut down, pump overrun (refer to section 5.4 "Pump overrun
and mixing valve overrun") also acts on the bypass pump.
In addition to activating the bypass pump, locking signals are generated if required and
when a return temperature sensor is connected. If this is not required, setting "None" can
be selected for "Lock sig maintained boil ret temp".
If no return temperature is available, the bypass pump will be controlled parallel to
burner operation. The bypass pump always runs when released and when the basic
burner stage is on.
When using a boiler with mixing valve in the boiler return (plant type H4-x), maintained
boiler return temperature will be ensured by the separate mixing valve.
Modular Heating Controller RMH760B
6 Boiler temperature control
Range
0...20 K
TBoR
TBoRmin+SDByP
TBoRmin
20 30
t [min]
t
TiOverrunCnsm
t
Factory setting
6 K
83/238
CE1P3133en
05.02.2007